官方文件：https://pay.weixin.qq.com/wiki/doc/api/H5.php?chapter=15_1

開發之前確認開通了H5支付功能

一、安裝微信sdk

 二、建立config類

package com.xiuchefang.config;

import com.github.wxpay.sdk.WXPayConfig;

import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;

 
/**
 * Created by 15117 on 2018/11/27.
 */
public class XCFWXPayConfig implements WXPayConfig {

    private byte[] certData;

    public XCFWXPayConfig() throws Exception {
        String certPath = "***";
        File file = new File(certPath);
        InputStream stream = new FileInputStream(file);
        
 
this.certData = new byte[(int)file.length()];
        stream.read(this.certData);
        stream.close();
    }

    @Override
    public String getAppID() {
        return "***";
    }

    @Override
    public String getMchID() {
        return "***";
    }

    @Override
    public String getKey() {
        
 
return "***";
    }

    @Override
    public InputStream getCertStream() {
        return new ByteArrayInputStream(this.certData);
    }

    @Override
    public int getHttpConnectTimeoutMs() {
        return 8000;
    }

    @Override
    public int getHttpReadTimeoutMs() {
        return 10000;
    }
}

三、呼叫微信支付介面下單

　　使用者ip獲取　　

　（1）微信使用者ip獲取指引：https://pay.weixin.qq.com/wiki/doc/api/H5.php?chapter=15_5

　（2）程式碼獲取ip指引：https://www.cnblogs.com/SongG-blogs/p/9083512.html

      *注意抽象方法作用域

　　支付簽名錯誤排產方法

　　1、確認公眾號的appSecret和商戶號的API金鑰沒有搞混。

　　2、重置商戶API金鑰（注意專案中記得更新api金鑰）

　　3、確認公眾號授權的域名和目錄是正確的

　　　針對redirect_url處理

　　前臺進行頁面跳轉

支付成功之後處理，微信請求notify_url

@Override
    public synchronized void payNotify(HttpServletRequest request, HttpServletResponse response) {

        System.out.println("微信支付回撥");
        try {
            String resXml = "";
            XCFWXPayConfig xcfwxPayConfig = new XCFWXPayConfig();
            WXPay wxPay = new WXPay(xcfwxPayConfig);

            InputStream inStream = request.getInputStream();
            ByteArrayOutputStream outSteam = new ByteArrayOutputStream();
            byte[] buffer = new byte[1024];
            int len = 0;
            while ((len = inStream.read(buffer)) != -1) {
                outSteam.write(buffer, 0, len);
            }
            outSteam.close();
            inStream.close();
            String result = new String(outSteam.toByteArray(), "utf-8");// 獲取微信呼叫我們notify_url的返回資訊
            Map<String, String> map = WXPayUtil.xmlToMap(result);

            if (wxPay.isPayResultNotifySignatureValid(map)) {
                System.out.println("微信支付-簽名驗證成功");
                resXml = "<xml>" + "<return_code><![CDATA[SUCCESS]]></return_code>"
                        + "<return_msg><![CDATA[OK]]></return_msg>" + "</xml> ";
                //業務處理開始
                
                //業務處理結束
            }
            BufferedOutputStream out = new BufferedOutputStream(response.getOutputStream());
            out.write(resXml.getBytes());
            out.flush();
            out.close();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

其它常見錯誤解決辦法（https://pay.weixin.qq.com/wiki/doc/api/H5.php?chapter=15_4）